Antistatic flame-retardant polyamide 66 resin as well as preparation method and application thereof

Abstract

The invention provides antistatic flame-retardant polyamide 66 resin and a preparation method and application thereof.The antistatic flame-retardant polyamide 66 resin is prepared from polyamide 66 salt, a composite additive and a catalyst in specific parts, and the composite additive comprises an organic reactive flame retardant and an inorganic flame retardant; the organic reactive flame retardant and the inorganic flame retardant are jointly subjected to ball milling to obtain the flame retardant; by adding the specific composite additive, the dispersion uniformity of the composite additive in a polyamide 66 resin matrix can be effectively improved, the flame retardance of the material is improved, meanwhile, the addition amount of the flame retardant is reduced, the charring rate of the material is increased, and the compactness of a carbon layer is improved; in addition, the obtained antistatic flame-retardant polyamide 66 resin also has the characteristic of excellent spinnability, and is suitable for preparing antistatic flame-retardant polyamide 66 cellosilk with excellent mechanical properties and flame retardance.

Description

Technical Field

[0001] This invention belongs to the field of polyamide technology, specifically relating to an antistatic flame-retardant polyamide 66 resin, its preparation method, and its application. Background Technology

[0002] In traditional industry, flame-retardant PA66 spinning grade resin is usually prepared by adding flame retardants, which has the advantages of simple process and low cost. However, it has the disadvantages of large amount of flame retardant added and uneven distribution, resulting in slow flame retardant speed and short flame retardant effect, and also has a significant impact on the mechanical properties of the material. On the other hand, using flame retardants as comonomers and attaching them to the polyamide molecular chain by chemical bond is a current research hotspot. This method can reduce the amount of flame retardant added and has little impact on the mechanical properties of polyamide resin.

[0003] For example, CN104945658A discloses a reactive halogen-free flame retardant, bis-(p-aminocarboxyphenyl)phenylphosphine oxide (BCNPO), its synthesis method, and its application; it includes forming a salt of bis-(p-aminocarboxyphenyl)phenylphosphine oxide with hexamethylenediamine, and then copolymerizing it with nylon 66 salt at an addition amount of 5% (molar percentage), and the resulting copolymer flame-retardant nylon can achieve a UL94 V0 flame retardant level. For example, CN108384054A discloses a flame retardant, bis-N-phenyl-3-amino-melamine-phenylphosphamide. This involves uniformly mixing bis-N-1-phenyl-3-amino-melamine-phenylphosphamide with a carboxyl-containing resin, reacting and melt-extruding the mixture, and grafting the bis-N-1-phenyl-3-amino-melamine-phenylphosphamide onto the carboxyl groups of the resin to obtain a flame-retardant PA66 resin. Results show that the introduction of bis-N-1-phenyl-3-amino-melamine-phenylphosphamide increases the initial decomposition temperature and maximum decomposition temperature of the PA66 composite material. When the content is 7 wt%, the limiting oxygen index reaches 28, the vertical burning method reaches V-0, and there is no dripping ignition, demonstrating excellent flame-retardant performance.

[0004] However, research has revealed that the flame-retardant polyamide 66 resin provided by the aforementioned existing technology still has the following drawbacks: First, the charring efficiency is slow and the charring properties need to be improved, possibly because both are mainly gas-phase flame retardants; second, the amount of flame retardant added is relatively large, which affects the final mechanical properties of the material and is also costly.

[0005] Therefore, in order to address the above-mentioned technical problems, there is an urgent need to develop an antistatic flame-retardant polyamide 66 resin with low flame retardant addition, fast charring rate, and excellent mechanical properties. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an antistatic flame-retardant polyamide 66 resin, its preparation method and application. The antistatic flame-retardant polyamide 66 resin has a fast char formation rate, high char layer density and high extreme oxygen index, and has excellent flame retardant properties, as well as excellent mechanical properties.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an antistatic flame-retardant polyamide 66 resin, wherein the raw materials for preparing the antistatic flame-retardant polyamide 66 resin comprise the following components in parts by weight:

[0009] 90-120 parts by weight of polyamide 66 salt;

[0010] 1-14 parts by weight of compound additive;

[0011] Catalyst: 0.1 to 1 part by weight;

[0012] The composite additive includes an organic reactive flame retardant and an inorganic flame retardant, and is obtained by ball milling the organic reactive flame retardant and the inorganic flame retardant together.

[0013] The raw materials for preparing the antistatic flame-retardant polyamide 66 resin provided by this invention include specific proportions of polyamide 66 salt, composite additives, and a catalyst. The composite additives include an organic reactive flame retardant and an inorganic flame retardant, obtained by ball milling the organic reactive flame retardant and the inorganic flame retardant together. On one hand, by combining the organic reactive flame retardant and the inorganic flame retardant, they can achieve a synergistic effect, improving the flame-retardant performance of the material while reducing the amount of flame retardant added. Specifically, the composite additive formed by the combination can quickly form a stable flame-retardant layer on the material surface, thereby preventing flame propagation and contact with oxygen, slowing down the combustion rate and reducing smoke production. Simultaneously, the addition of the inorganic flame retardant can also act as a rigid particle plasticizer and reinforcement, thus helping to improve the flame-retardant and mechanical properties of the material. On the other hand, further... The composite additive is obtained by ball milling an organic reactive flame retardant and an inorganic flame retardant together. During the ball milling process, the organic reactive flame retardant and the inorganic flame retardant are not simply physically mixed. The organic reactive flame retardant can coat or adsorb onto the inorganic flame retardant, which can prevent the agglomeration of the inorganic flame retardant and improve the compatibility of both with the polyamide 66 resin matrix, reducing phase separation. This improves the dispersion uniformity of the resulting composite additive in the matrix. Even with a low addition amount, the resulting polyamide 66 fibers can have excellent flame retardancy with minimal impact on the mechanical properties of the polyamide 66 resin. It is particularly suitable for spinning-grade polyamide 66 resin, solving the problems of high flame retardant addition, poor charring effect, poor mechanical properties, and easy breakage during spinning in existing flame-retardant polyamide 66 resins containing phosphorus-based flame retardants.

[0014] The polyamide 66 salt can be 90 parts by weight, 95 parts by weight, 100 parts by weight, 105 parts by weight, 110 parts by weight, 115 parts by weight, or 120 parts by weight, etc.

[0015] The weight of the composite additive can be 1 part by weight, 1.4 parts by weight, 1.6 parts by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 12 parts by weight, 13 parts by weight, or 14 parts by weight, etc.

[0016] The catalyst may be 0.1 parts by weight, 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, or 1 part by weight, etc.

[0017] In this invention, there are no special restrictions on the source of the polyamide 66 salt; commercially available products can be purchased directly or polyamide 66 salt solutions can be prepared according to existing processes.

[0018] For example, the method for preparing the polyamide 66 salt solution includes: reacting adipic acid and hexamethylenediamine in demineralized water to obtain the polyamide 66 salt solution.

[0019] Optionally, the molar ratio of hexamethylenediamine to adipic acid can be (1 to 1.005):1, such as 1:1, 1.001:1, 1.002:1, 1.003:1, 1.004:1 or 1.005:1, etc.

[0020] Optionally, the reaction temperature is 65–80°C, for example, 65°C, 70°C, 75°C, or 80°C.

[0021] Optionally, the polyamide 66 salt in the polyamide 66 salt solution has a mass percentage content of 50-60%, such as 50%, 52%, 54%, 56%, 58%, or 60%.

[0022] In some preferred embodiments, the mass ratio of the organic reactive flame retardant to the inorganic flame retardant is (1-5):1, for example, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, or 5:1, etc.; and in the composite additive, the content of the organic reactive flame retardant is 0.5-7 parts by weight, for example, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, or 7 parts by weight, etc.; and the content of the inorganic flame retardant is 0.5-2 parts by weight, for example, 0.5 parts by weight, 0.7 parts by weight, 0.9 parts by weight, 1.1 parts by weight, 1.3 parts by weight, 1.5 parts by weight, 1.7 parts by weight, 1.9 parts by weight, or 2 parts by weight, etc.

[0023] In some preferred embodiments, the average particle size of the composite additive is 0.1–3 μm, for example, 0.1 μm, 0.3 μm, 0.9 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.1 μm, 2.5 μm, 2.7 μm, 2.9 μm, or 3 μm, and more preferably 0.5–1 μm. If the average particle size of the composite additive is too large, it will easily lead to a deterioration in the mechanical properties of the obtained antistatic flame-retardant polyamide 66 resin; if the average particle size of the composite additive is too small, it will make the preparation of the obtained antistatic flame-retardant polyamide 66 resin more difficult.

[0024] In some preferred embodiments, the organic reactive flame retardant includes any one or a combination of at least two of bis-(p-benzoic acid)-phenyl-phosphoramide, bis-(p-benzoic acid)-phenyl-phosphoramide-hexanediamine pre-flame retardant, or bis-N-phenyl-3-amino-melamine-phenylphosphoramide-adipic acid pre-flame retardant.

[0025] In some preferred embodiments, before ball milling, the average particle size of the inorganic flame retardant is 1 to 6 μm, for example, 1 μm, 2 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm or 6 μm.

[0026] In this invention, the average particle size of the composite additive and the inorganic flame retardant is obtained by laser particle size analyzer.

[0027] In some preferred embodiments, the inorganic flame retardant includes any one or a combination of at least two of zinc borate, calcium oxide, zinc oxide, or aluminum oxide, with zinc borate being more preferred.

[0028] In some preferred embodiments, the raw materials for preparing the antistatic flame-retardant polyamide 66 resin also include 0.1 to 5 parts by weight of an antistatic agent, such as 0.1 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, or 5 parts by weight.

[0029] In some other preferred embodiments, the composite additive further includes 0.1 to 5 parts by weight of an antistatic agent (e.g., 0.1 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, or 5 parts by weight); and the composite additive is obtained by ball milling the organic reactive flame retardant, the inorganic flame retardant, and the antistatic agent together.

[0030] In some preferred embodiments, the antistatic agent includes an amphoteric antistatic agent.

[0031] In some preferred embodiments, the amphoteric antistatic agent includes any one or a combination of at least two of dodecyl dimethyl quaternary acetate, dodecyl dicarboxymethyl ammonium acetate, or alkyl dicarboxymethyl ammonium acetate.

[0032] During the research process, the inventors of this invention creatively discovered that, on the one hand, the addition of the antistatic agent can quickly dissipate the static electricity generated by friction during the transportation and production of polyamide 66 resin. Furthermore, when polyamide 66 resin is used for spinning, the antistatic agent has strong adhesion to the resin, forming conductive channels on its surface. This allows the charge to be quickly removed from the resin surface, thus exhibiting excellent antistatic properties. This optimizes the chip transportation effect, improves spinning stability, and enhances fiber processing performance. In addition, the antistatic agent can also improve the fiber's softness and durability, reducing the risk of dust adsorption and static sparks generated during processing due to friction. This results in significantly fewer filament breaks during spinning, less static electricity generation during high-speed winding, and a significantly lower volume resistivity. The antistatic effect is significant. Further, amphoteric antistatic agents are preferred, as their greatest advantage is their ability to be used in combination with anionic or cationic agents, resulting in a wide range of applications. On the other hand, the inventors of this invention have also discovered that the antistatic agent can improve the dispersibility of flame retardants, especially for specific antistatic agents such as dodecyl dimethyl quaternary ethylene glycol. Since these antistatic agents typically contain long carbon chains and lipophilic groups, they facilitate uniform dispersion in the polyamide 66 resin matrix and can alleviate the agglomeration of flame retardants by forming a flexible interface layer. Furthermore, when the organic reactive flame retardant, the inorganic flame retardant, and the antistatic agent are ball-milled together, it further helps prevent the agglomeration of the inorganic flame retardant, further improving compatibility with the polyamide 66 resin matrix, reducing phase separation, and thus improving the uniform dispersion of the resulting composite additive in the matrix.

[0033] In some preferred embodiments, the ball mill rotates at a speed of 200 to 500 rpm, such as 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm.

[0034] In some preferred embodiments, the ball milling time is 15 to 120 minutes, such as 15 minutes, 20 minutes, 40 minutes, 60 minutes, 80 minutes, 100 minutes, or 120 minutes.

[0035] In some preferred embodiments, the ball milling includes wet ball milling or dry ball milling, and is more preferably wet ball milling.

[0036] In the wet ball milling process, the solvent used is the solvent used in the polyamide 66 salt polymerization (e.g., demineralized water). During the wet ball milling process, hydrogen bonds or ionic bonds will exist between the metal ions in the inorganic flame retardant and the organic reactive flame retardant, which is conducive to promoting the adsorption of the organic reactive flame retardant on the surface of the inorganic flame retardant, thereby further helping to increase the dispersibility of the obtained composite additive in the polyamide 66 resin.

[0037] In some preferred embodiments, the dry ball milling time is 15 to 90 minutes, for example, 15 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, or 90 minutes.

[0038] In some preferred embodiments, the wet ball milling time is 30 to 120 minutes, such as 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, or 120 minutes.

[0039] In this invention, there is no special limitation on the type of catalyst, and any catalyst commonly used in the art can be selected; for example, the catalyst includes any one or a combination of at least two of sodium hypophosphite, sodium phenylhypophosphite, or zinc hypophosphite.

[0040] In some preferred embodiments, the raw materials for preparing the antistatic flame-retardant polyamide 66 resin further include 0.1 to 1 part by weight of a heat stabilizer (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 part by weight). The heat stabilizer improves the heat resistance of the polyamide 66 resin during processing, prevents molecular chain degradation due to high molecular weight, maintains its physicochemical properties, and thus extends its service life.

[0041] In this invention, there are no special restrictions on the type of heat stabilizer; commonly used heat stabilizers in the art can be selected.

[0042] For example, the heat stabilizer includes any one or a combination of at least two of phosphite stabilizers, hindered amine stabilizers, or triazine stabilizers.

[0043] For example, the phosphite stabilizer includes tris(2,4-di-tert-butylphenyl) phosphite; the hindered amine stabilizer includes 2,2,6,6-tetramethylpiperidine.

[0044] In a second aspect, the present invention provides a method for preparing the antistatic flame-retardant polyamide 66 resin as described in the first aspect, the method being as follows:

[0045] The first method is when the composite additive does not contain an antistatic agent (i.e., the antistatic agent is added alone as a raw material for the preparation of antistatic flame-retardant polyamide 66 resin, without being ball-milled together with organic reactive flame retardants and inorganic flame retardants), which includes: mixing polyamide 66 salt solution, composite additive, catalyst, optional thermal stabilizer and optional antistatic agent, and the resulting mixture is concentrated and polymerized to obtain the antistatic flame-retardant polyamide 66 resin;

[0046] Alternatively, the second method involves mixing a polyamide 66 salt solution, a composite additive, a catalyst, and an optional geothermal stabilizer, followed by concentration and polymerization to obtain polyamide 66 resin.

[0047] As described above, in the preparation method of antistatic flame-retardant polyamide 66 resin provided by the present invention, regardless of whether it is the first method or the second method, the heat stabilizer is added before the concentration and polymerization reaction, that is, after the polyamide 66 salt is mixed with it in the salt formation stage before the concentration and polymerization reaction is carried out; adding the heat stabilizer at this stage can effectively suppress thermal degradation and yellowing caused by high shear and high pressure; in addition, by adding the heat stabilizer at this stage, the thermal stability of the material can be better controlled in subsequent processing, ensuring the quality and performance of the final product.

[0048] Furthermore, in the first method, the antistatic agent is not added to the composite additive. Instead, it is added before the concentration and polymerization reaction. This can also improve the dispersibility of the composite additive in the polyamide 66 resin matrix. In particular, for specific antistatic agents such as dodecyl dimethyl quaternary ethylene glycol, since these antistatic agents usually contain long carbon chains and lipophilic groups, they help to improve the uniform dispersion of the composite additive in the polyamide 66 resin matrix and may alleviate the agglomeration of the composite additive by forming a flexible interface layer.

[0049] In addition, in the second method, the composite additive contains an antistatic agent. The antistatic agent can not only play the role of the first method, improving the dispersibility of the composite additive in the polyamide 66 resin matrix, but also, by adding the antistatic agent during the ball milling process, it can further prevent the agglomeration of inorganic flame retardants, thereby further improving the dispersion uniformity of the obtained composite additive in the polyamide 66 resin matrix.

[0050] In summary, the antistatic flame-retardant polyamide 66 resin prepared by the above method has the characteristics of low flame retardant content, uniform dispersion, good flame retardant effect, and significant antistatic effect.

[0051] In some preferred embodiments, the polyamide 66 salt in the polyamide 66 salt solution has a mass percentage content of 50-60%, such as 50%, 52%, 54%, 56%, 58%, or 60%.

[0052] In some preferred embodiments, the concentration temperature is 150-160°C, such as 150°C, 151°C, 152°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C, or 160°C.

[0053] In some preferred embodiments, the mass percentage of polyamide 66 salt in the concentrated salt solution obtained after concentration is 70-80%, such as 70%, 72%, 74%, 76%, 78%, or 80%.

[0054] In some preferred embodiments, the polymerization reaction specifically includes: 1) feeding the concentrated salt solution obtained after concentration into the polymerization reactor as the reactant, and reacting it for 0.5 to 1.5 h (e.g., 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h, or 1.5 h) under a pressure of 1 to 2 MPa (e.g., 1 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, or 1.8 MPa, etc.), with the temperature of the resulting reactant being 220 to 260°C (e.g., 220°C, 230°C, 240°C, 250°C, or 260°C, etc.); 2) after unloading to atmospheric pressure, raising the temperature of the reactant to 270 to 280°C (e.g., 270 to 280°C, etc.). (e.g., 270℃, 272℃, 274℃, 276℃, 278℃ or 280℃, etc.); 3) Evacuate to 0~0.1MPa (e.g. 0MPa, 0.02MPa, 0.04MPa, 0.06MPa, 0.08MPa or 0.1MPa, etc.), react for 5~10min (e.g. 5min, 6min, 7min, 8min, 9min or 10min, etc.); 4) Pressurize to 0.2~0.4MPa (e.g. 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa or 0.4MPa, etc.), cool and pelletize to obtain the antistatic flame-retardant polyamide 66 resin.

[0055] Thirdly, the present invention provides an antistatic flame-retardant polyamide 66 fiber filament, wherein the material of the antistatic flame-retardant polyamide 66 fiber filament comprises the antistatic flame-retardant polyamide 66 resin as described in the first aspect.

[0056] The antistatic and flame-retardant polyamide 66 fiber provided by this invention can reach the V-0 level in UL-94 testing. It also has a certain antistatic effect, which helps to maintain the stability of the spinning process, reduce fiber breakage and entanglement, improve fiber softness, improve fiber quality, and make the resulting fiber more uniform and smooth.

[0057] Fourthly, the present invention provides a method for preparing antistatic flame-retardant polyamide 66 fiber filaments as described in the third aspect, wherein the preparation method comprises: melt spinning antistatic flame-retardant polyamide 66 resin to obtain the antistatic flame-retardant polyamide 66 fiber filaments.

[0058] In some preferred embodiments, the melt spinning process further includes drying at 100–110°C (e.g., 100°C, 105°C, or 110°C) until the water content is below 600 ppm.

[0059] In some preferred embodiments, the melt spinning temperature is 275-285°C, such as 275°C, 277°C, 279°C, 281°C, 283°C, or 285°C.

[0060] In some preferred embodiments, the melt spinning is carried out in a spinning machine, wherein the four heating zones of the spinning machine are respectively 275–280°C (e.g., 275°C, 276°C, 277°C, 278°C, 278°C, or 280°C), 275–282°C (e.g., 275°C, 276°C, 277°C, 278°C, 278°C, 280°C, or 282°C), 275–285°C (e.g., 275°C, 276°C, 277°C, 278°C, 278°C, 280°C, 282°C, or 285°C), and 275–280°C. 5℃ (e.g., 275℃, 276℃, 277℃, 278℃, 278℃, 280℃, 282℃, or 285℃, etc.), melt pipe temperature 275~285℃ (e.g., 275℃, 276℃, 277℃, 278℃, 278℃, 280℃, 282℃, or 285℃, etc.), tank temperature 280~285℃ (e.g., 280℃, 281℃, 282℃, 283℃, 284℃, or 285℃, etc.), metering pump temperature 275~285℃ (e.g., 275℃, 276℃, 277℃, 278℃, etc.). Temperatures range from 278℃, 280℃, 282℃, or 285℃, etc.; metering pump flow rates are 15–25 mL / min (e.g., 15 mL / min, 17 mL / min, 19 mL / min, 21 mL / min, 23 mL / min, or 25 mL / min, etc.); and the rotational speeds of the two pairs of drafting rollers are each independently 1000–2800 m / min (e.g., 1000 m / min, 1400 m / min, 1800 m / min, 2200 m / min, 2400 m / min, or 2800 m / min, etc.). The guide disc speed is 1000-3000 m / min (e.g., 1000 m / min, 1500 m / min, 2000 m / min, 2500 m / min or 3000 m / min, etc.), the winding roller speed is 3500-3900 m / min (e.g., 3500 m / min, 3550 m / min, 3600 m / min, 3700 m / min, 3800 m / min or 3900 m / min, etc.), and the traction ratio is 1.5-3.5 (e.g., 1.5, 2, 2.5, 3 or 3.5, etc.).

[0061] Fifthly, the present invention provides the application of antistatic flame-retardant polyamide 66 fiber as described in the third aspect in the manufacture of automobiles or electronic appliances.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] The raw materials for the antistatic flame-retardant polyamide 66 resin provided by this invention include specific proportions of polyamide 66 salt, composite additives, and catalysts. The composite additives include organic reactive flame retardants and inorganic flame retardants, and are obtained by ball milling the organic reactive flame retardant and the inorganic flame retardant together. By adding the above-mentioned specific composite additives, not only can the dispersion uniformity of the composite additives in the polyamide 66 resin matrix be effectively improved, and the amount of flame retardant added can be reduced while improving the flame retardancy of the material, but it also helps to accelerate the char formation rate of the material and improve the density of the char layer. At the same time, it also has the characteristics of excellent spinnability, making it suitable for preparing antistatic flame-retardant polyamide 66 fibers with both excellent mechanical properties and flame retardant properties. Detailed Implementation

[0064] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0065] (1) Organic reactive flame retardants

[0066] Bis-(p-benzoic acid)-phenyl-phosphoramide (BCNPO): Its structural formula is as follows The preparation method is referenced in CN104945658A.

[0067] BCNPO-hexanediamine pre-flame retardant: prepared in-house according to the following method;

[0068] The preparation method includes: dissolving BCNPO in a 10wt% hexamethylenediamine aqueous solution (the molar ratio of BCNPO to hexamethylenediamine is 1:1) to prepare a BCNPO-hexamethylenediamine pre-flame retardant solution.

[0069] (2) Inorganic flame retardants

[0070] Zinc borate: with an average particle size of 3-5 μm, purchased from Jinan Yinqingxin Materials Co., Ltd., model ZB-2335.

[0071] Zinc oxide: average particle size is 1-5 μm, commercially available.

[0072] (3) Catalyst: Sodium hypophosphite, commercially available.

[0073] (4) Heat stabilizer: Tris(2,4-di-tert-butylphenyl) phosphite, commercially available.

[0074] (5) Antistatic agents: Dodecyl dimethyl quaternary ethylamine or dodecyl diethanolamine, both of which are commercially available.

[0075] Preparation Example 1

[0076] A composite additive is prepared by means of: placing BCNPO-hexanediamine pre-flame retardant solution, zinc borate and dodecyl dimethyl quaternary ethyl salt in a ball mill at a solid mass ratio of 3:1:0.3, and performing wet ball milling at room temperature. The solvent for wet ball milling is demineralized water. After ball milling, a composite additive with an average particle size of 0.5 μm is obtained.

[0077] Preparation Example 2

[0078] A composite additive is prepared by means of: placing BCNPO-hexanediamine pre-flame retardant solution, zinc borate and dodecyl dimethyl quaternary ethyl salt in a ball mill at a solid mass ratio of 3:1:2.5, and performing wet ball milling at room temperature. The solvent for wet ball milling is demineralized water. After ball milling, a composite additive with an average particle size of 0.5 μm is obtained.

[0079] Preparation Example 3

[0080] A composite additive is prepared by means of: placing BCNPO-hexamethylenediamine pre-flame retardant solution and zinc borate in a ball mill at a solid mass ratio of 3:1, and performing wet ball milling at room temperature. The solvent for wet ball milling is desalinated water, and the ball milling time is 120 min. After ball milling, a composite additive with an average particle size of 0.5 μm is obtained.

[0081] Preparation Example 4

[0082] A composite additive is prepared by means of: placing a BCNPO-hexanediamine pre-flame retardant solution and zinc borate in a ball mill at a solid mass ratio of 4:1, and performing wet ball milling at room temperature. The solvent for wet ball milling is desalinated water. After ball milling, a composite additive with an average particle size of 0.5 μm is obtained.

[0083] Preparation Example 5

[0084] A composite additive is prepared by means of: placing a BCNPO-hexanediamine pre-flame retardant solution and zinc borate in a ball mill at a solid mass ratio of 2:1, and performing wet ball milling at room temperature. The solvent for wet ball milling is desalinated water. After ball milling, a composite additive with an average particle size of 1 μm is obtained.

[0085] Preparation Example 6

[0086] A composite additive differs from Preparation Example 3 in that the average particle size of the composite additive obtained after wet ball milling is 2 μm by changing the wet ball milling time, while the other substances, amounts and parameters are the same as in Preparation Example 3.

[0087] Preparation Example 7

[0088] A composite additive differs from Preparation Example 3 in that the average particle size of the composite additive obtained after ball milling is 3 μm by adjusting the wet ball milling time, while the other substances, amounts and parameters are the same as in Preparation Example 3.

[0089] Preparation Example 8

[0090] A composite additive is prepared by means of: placing BCNPO flame retardant and zinc borate in a ball mill at a mass ratio of 3:1 and performing wet ball milling at room temperature. The solvent for wet ball milling is desalinated water. After ball milling, a composite additive with an average particle size of 0.5 μm is obtained.

[0091] Preparation Example 9

[0092] A composite additive is prepared by means of: first, evaporating the water in the BCNPO-hexanediamine pre-flame retardant solution to obtain the BCNPO-hexanediamine pre-flame retardant; then, placing the BCNPO-hexanediamine pre-flame retardant and zinc borate in a ball mill at a mass ratio of 3:1 and performing dry ball milling at room temperature for 120 min to obtain the composite additive.

[0093] Preparation Example 10

[0094] A composite additive, which differs from Preparation Example 3 in that zinc oxide is used instead of zinc borate, while other substances, amounts and parameters are the same as in Preparation Example 3.

[0095] Preparation Example 11

[0096] A composite additive differs from Preparation Example 3 in that the solid mass ratio of BCNPO-hexanediamine pre-flame retardant solution to zinc borate is 0.5:1, while other substances, amounts, and parameters are the same as in Preparation Example 3.

[0097] Preparation Example 12

[0098] A composite additive differs from Preparation Example 3 in that the solid mass ratio of BCNPO-hexanediamine pre-flame retardant solution to zinc borate is 7:1, while other substances, amounts, and parameters are the same as in Preparation Example 3.

[0099] Preparation Example 13

[0100] A composite additive, which differs from Preparation Example 3 in that dodecyl diethanolamine is used instead of dodecyl dimethyl quaternary ethylamine, while the other substances, amounts and parameters are the same as those in Preparation Example 3.

[0101] Comparative Preparation Example 1

[0102] A mixed flame retardant is prepared by directly mixing a BCNPO-hexamethylenediamine pre-flame retardant solution with a solid mass ratio of 3:1 and zinc borate at room temperature to obtain the mixed flame retardant.

[0103] Example 1

[0104] Example 1 provides an antistatic flame-retardant polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 4.3 parts by weight of the composite additive provided in Preparation Example 1, 0.9 parts by weight of heat stabilizer, and 0.5 parts by weight of catalyst.

[0105] The method for preparing antistatic flame-retardant polyamide 66 resin provided in this embodiment includes the following steps:

[0106] (1) Adipic acid and hexamethylenediamine in a molar ratio of 1:1 were added to demineralized water in sequence and reacted at 70°C to obtain a polyamide 66 salt solution with a mass percentage of 55%.

[0107] (2) Add the composite additive, catalyst and heat stabilizer provided in Preparation Example 1 to the polyamide 66 salt solution obtained in step (1), stir thoroughly, and then send it to a concentration tank for concentration. Raise the concentration temperature to 155°C to obtain a concentrated salt solution with a polyamide 66 salt mass percentage of 75%.

[0108] (3) The concentrated salt solution described in step (2) is fed into the polymerization reactor as a reactant. The temperature and pressure are first increased to 220°C and 1.8 MPa, and maintained at 1.80 MPa for 50 min. During the maintenance process, the reactant is gradually heated to 255°C. Then the pressure inside the polymerization reactor is slowly reduced to atmospheric pressure (the pressure reduction period is 55 min). During the pressure reduction process, the temperature of the reactant is simultaneously increased to 275°C. Then the vacuum is drawn to -0.05 MPa and the reaction is maintained at this pressure for 6 min to further increase the viscosity of the product. Finally, the polymerization reactor is pressurized to 0.3 MPa, cooled, and pelletized to obtain the antistatic flame-retardant polyamide 66 resin.

[0109] Example 2

[0110] Example 2 provides an antistatic flame-retardant polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 6.5 parts by weight of the composite additive provided in Preparation Example 2, 0.9 parts by weight of heat stabilizer, and 0.5 parts by weight of catalyst.

[0111] The preparation method of the antistatic flame-retardant polyamide 66 resin provided in this embodiment is the same as that in Example 1.

[0112] Example 3

[0113] Example 3 provides an antistatic and flame-retardant polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 4 parts by weight of the composite additive provided in Preparation Example 3, 0.3 parts by weight of dodecyl dimethyl quaternary ethylene glycol salt, 0.9 parts by weight of heat stabilizer, and 0.5 parts by weight of catalyst.

[0114] The method for preparing antistatic flame-retardant polyamide 66 resin provided in this embodiment includes the following steps:

[0115] (1) Adipic acid and hexamethylenediamine in a molar ratio of 1:1 were added to demineralized water in sequence and reacted at 70°C to obtain a polyamide 66 salt solution with a mass percentage of 55%.

[0116] (2) Add the composite additive, dodecyl dimethyl quaternary ethyl salt, catalyst and heat stabilizer provided in Preparation Example 3 to the polyamide 66 salt solution obtained in step (1), stir thoroughly, and then send it to a concentration tank for concentration. The concentration temperature is 155°C to obtain a concentrated salt solution with a polyamide 66 salt mass percentage of 75%.

[0117] (3) The concentrated salt solution described in step (2) is fed into the polymerization reactor as a reactant. The temperature and pressure are first increased to 220°C and 1.80 MPa, and maintained at 1.80 MPa for 50 minutes. During the maintenance process, the temperature of the reactant gradually rises to 255°C. Then the pressure inside the polymerization reactor is slowly reduced to atmospheric pressure (the pressure reduction time is 55 minutes). During the pressure reduction process, the temperature of the reactant is simultaneously increased to 275°C. Then the vacuum is drawn to -0.05 MPa, and the reaction is maintained at this pressure for 6 minutes to further increase the viscosity of the product. Finally, the polymerization reactor is pressurized to 0.3 MPa, cooled, and pelletized to obtain the antistatic flame-retardant polyamide 66 resin.

[0118] Example 4

[0119] Example 4 provides an antistatic and flame-retardant polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 5 parts by weight of the composite additive provided in Preparation Example 4, 2.5 parts by weight of dodecyl dimethyl quaternary ethylene glycol salt, 0.9 parts by weight of heat stabilizer, and 0.8 parts by weight of catalyst.

[0120] The preparation method of the antistatic flame-retardant polyamide 66 resin provided in Example 4 is the same as that in Example 3.

[0121] Example 5

[0122] Example 5 provides an antistatic flame-retardant polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 3 parts by weight of the composite additive provided in Preparation Example 5, 1 part by weight of dodecyl dimethyl quaternary ethylene glycol salt, 0.5 parts by weight of heat stabilizer, and 0.5 parts by weight of catalyst.

[0123] The preparation method of the antistatic flame-retardant polyamide 66 resin provided in Example 5 is the same as that in Example 3.

[0124] Example 6

[0125] Example 6 provides an antistatic and flame-retardant polyamide 66 resin, which differs from Example 3 in that the composite additive provided in Preparation Example 6 is replaced with an equal part by weight of the composite additive provided in Preparation Example 3, while the other substances, amounts and preparation methods are the same as in Example 3.

[0126] Example 7

[0127] Example 7 provides an antistatic and flame-retardant polyamide 66 resin, which differs from Example 3 in that the composite additive provided in Preparation Example 7 is replaced with an equal part by weight of the composite additive provided in Preparation Example 3. Other substances, amounts and preparation methods are the same as in Example 3.

[0128] Example 8

[0129] Example 8 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that the composite additive provided in Preparation Example 8 is replaced with an equal part by weight of the composite additive provided in Preparation Example 3, while the other substances, amounts and preparation methods are the same as in Example 3.

[0130] Example 9

[0131] Example 9 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that the composite additive provided in Preparation Example 9 is replaced with an equal weight of the composite additive provided in Preparation Example 3, while the other substances, amounts and preparation methods are the same as in Example 3.

[0132] Example 10

[0133] Example 10 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that an equal weight portion of the composite additive provided in Preparation Example 10 is used to replace the composite additive provided in Preparation Example 3. Other substances, amounts, and preparation methods are the same as in Example 3.

[0134] Example 11

[0135] Example 11 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that the composite additive provided in Preparation Example 11 is replaced with an equal part by weight of the composite additive provided in Preparation Example 3, while the other substances, amounts and preparation methods are the same as in Example 3.

[0136] Example 12

[0137] Example 12 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that an equal weight portion of the composite additive provided in Preparation Example 12 is used to replace the composite additive provided in Preparation Example 3, while other substances, amounts, and preparation methods are the same as in Example 3.

[0138] Example 13

[0139] Example 13 provides an antistatic flame-retardant polyamide 66 resin, which differs from Example 3 in that an equal weight portion of the composite additive provided in Preparation Example 13 is used to replace the composite additive provided in Preparation Example 3, while other substances, amounts, and preparation methods are the same as in Example 3.

[0140] Comparative Example 1

[0141] Comparative Example 1 provides a polyamide 66 resin, which differs from Example 3 in that an equal part by weight of the mixed flame retardant provided in Comparative Example 1 is used to replace the composite additive provided in Preparation Example 3, while the other substances, amounts and preparation methods are the same as in Example 3.

[0142] Comparative Example 2

[0143] Comparative Example 2 provides a polyamide 66 resin, which differs from Example 3 in that 4 parts by weight of BCNPO-hexanediamine pre-flame retardant are used to replace 4 parts by weight of the composite additive provided in Preparation Example 3. Other substances, amounts and preparation methods are the same as in Example 3.

[0144] Comparative Example 3

[0145] Comparative Example 3 provides a polyamide 66 resin, which, measured in solid parts by weight, comprises the following components: 100 parts by weight of polyamide 66 salt, 4 parts by weight of the composite additive provided in Preparation Example 3, 0.3 parts by weight of dodecyl dimethyl quaternary ethylene glycol salt, 0.9 parts by weight of heat stabilizer, and 0.5 parts by weight of catalyst.

[0146] The preparation method of the antistatic flame-retardant polyamide 66 resin provided in this comparative example includes the following steps:

[0147] (1) Adipic acid and hexamethylenediamine in a molar ratio of 1:1 were added to demineralized water in sequence and reacted at 70°C to obtain a polyamide 66 salt solution with a mass percentage of 55%.

[0148] (2) Add the composite additive, dodecyl dimethyl quaternary ethylene salt and catalyst provided in Preparation Example 3 to the polyamide 66 salt solution obtained in step (1), stir thoroughly, and then send it to a concentration tank for concentration. The concentration temperature is 155°C to obtain a concentrated salt solution with a polyamide 66 salt mass percentage of 75%.

[0149] (3) First, the concentrated salt solution and heat stabilizer described in step (2) are fed into the polymerization reactor. The temperature and pressure are raised to 220°C and 1.80 MPa, and maintained at 1.80 MPa for 50 minutes. During the maintenance process, the temperature of the reactants gradually rises to 255°C. Then, the pressure inside the polymerization reactor is slowly reduced to atmospheric pressure for 55 minutes. During the depressurization process, the temperature of the reactants rises to 275°C. Then, the pressure is evacuated to -0.05 MPa and the reaction is maintained at this pressure for 6 minutes to further increase the viscosity of the product. Finally, the polymerization reactor is pressurized to 0.3 MPa, cooled, and pelletized to obtain the polyamide 66 resin.

[0150] Comparative Example 4

[0151] Comparative Example 4 provides a polyamide 66 resin, measured in solid parts by weight, the raw materials of which include the following components: 100 parts by weight of polyamide 66 salt, 4 parts by weight of the composite additive provided in Preparation Example 3, 0.3 parts by weight of dodecyl dimethyl quaternary ethylene glycol salt, 0.9 parts by weight of heat stabilizer and 0.5 parts by weight of catalyst.

[0152] The preparation method of the antistatic flame-retardant polyamide 66 resin provided in this comparative example includes the following steps:

[0153] (1) Adipic acid and hexamethylenediamine in a molar ratio of 1:1 were added to demineralized water in sequence and reacted at 70°C to obtain a polyamide 66 salt solution with a mass percentage of 55%.

[0154] (2) Add the composite additive, heat stabilizer and catalyst provided in Preparation Example 3 to the polyamide 66 salt solution obtained in step (1), stir thoroughly, and then send it to a concentration tank for concentration. The concentration temperature is 155°C to obtain a concentrated salt solution with a polyamide 66 salt mass percentage of 75%.

[0155] (3) The concentrated salt solution and dodecyl dimethyl quaternary ethylene salt described in step (2) are placed in a polymerization reactor. The temperature and pressure are first increased to 220°C and 1.80 MPa, and maintained at 1.80 MPa for 50 min. During the maintenance process, the temperature of the reactants gradually rises to 255°C. Then the pressure in the polymerization reactor is slowly reduced to atmospheric pressure for 55 min. During the depressurization process, the temperature of the reactants rises to 275°C. Then the vacuum is drawn to -0.05 MPa and the reaction is maintained at this pressure for 6 min to further increase the viscosity of the product. Finally, the polymerization reactor is pressurized to 0.3 MPa, cooled, and pelletized to obtain the polyamide 66 resin.

[0156] Comparative Example 5

[0157] Comparative Example 1 provides a polyamide 66 resin, which differs from Example 3 in that the amount of composite additive provided in Example 3 is 1 part by weight, the amount of dodecyl dimethyl quaternary ethylene oxide added is 0.5 parts by weight, and other substances, amounts and preparation methods are the same as in Example 3.

[0158] Application Example 1

[0159] Application Example 1 provides an antistatic flame-retardant polyamide 66 fiber filament, the preparation method of which includes: drying the antistatic flame-retardant polyamide 66 resin provided in Example 1 in a rotary drum under a vacuum of -100 kPa or higher and a temperature of 105°C until the water content is lower than 600 ppm, and then performing melt spinning in a spinning machine. The temperatures of the four heating zones of the spinning machine are 272°C, 274°C, 277°C and 280°C respectively, the melt pipe temperature is 280°C, the box temperature is 280°C, the metering pump temperature is 280°C, the metering pump flow rate is 18 mL / min, the rotation speeds of the two pairs of drawing rollers are 1100 m / min and 3740 m / min respectively, the rotation speeds of the guide discs are 1000 m / min and 3800 m / min respectively, the winding roller rotation speed is 3700 m / min, and the traction ratio is 3.0, thereby obtaining the antistatic flame-retardant polyamide 66 fiber filament.

[0160] Application Examples 2-13

[0161] Application Examples 2-13 each provide an antistatic flame-retardant polyamide 66 fiber filament. The difference from Application Example 1 is that the antistatic flame-retardant polyamide 66 resin provided in Examples 2-13 is used to replace the antistatic flame-retardant polyamide 66 resin provided in Example 1. All other conditions and parameters are the same as in Application Example 1.

[0162] Comparative Application Examples 1-5

[0163] Comparative Application Examples 1-5 each provide a polyamide 66 fiber filament. The difference from Application Example 1 is that the polyamide 66 resin provided in Comparative Examples 1-5 is used to replace the antistatic and flame-retardant polyamide 66 resin provided in Example 1. All other conditions and parameters are the same as in Application Example 1.

[0164] Performance testing of polyamide 66 resin:

[0165] (1) Notched impact strength of simply supported beams: The test was conducted in accordance with the method provided in GB / T 1043.1-2008 "Determination of impact performance of simply supported beams".

[0166] (2) Tensile strength and elongation at break: The test was conducted in accordance with the method provided in GB / T 1040.1-2008 "Determination of tensile properties of plastics".

[0167] (3) Limiting oxygen index: The test was conducted in accordance with the test method provided in GB / T2406.2-2009 "Oxygen index method for determination of combustion behavior".

[0168] (4) Charring effect: The test was conducted in accordance with the method provided in GB / T 2408-2021 "Determination of combustion performance by horizontal and vertical methods", including charring rate and charring density.

[0169] The polyamide 66 resins provided in Examples 1-13 and Comparative Examples 1-5 were tested using the above test methods, and the test results are shown in Table 1.

[0170] Table 1

[0171]

[0172] Performance testing of polyamide 66 fibers

[0173] (1) Full roll rate: refers to the ratio of the actual number of full rolls to the theoretically expected number of full rolls within the specified roll-down time. It can reflect the efficiency and quality of polyamide 66 fiber filaments in the production process.

[0174] (2) Maximum spinning speed: refers to the highest spinning speed that can ensure the spinnability, stability and quality of polyamide 66 fiber filaments of polyamide 66 resin during the spinning process.

[0175] (3) Breaking strength: Refer to GB / T 14344-2022 standard for tensile performance test of filament.

[0176] (4) Elongation at break: Refer to GB / T 14344-2022 standard for tensile performance test of filament.

[0177] The polyamide 66 fiber filaments (DTY filament-55D / 24f) provided in Application Examples 1 to 13 and Comparative Application Examples 1 to 5 were tested using the above test method. The test results are shown in Table 2.

[0178] Table 2

[0179] Full roll rate (%) Maximum spinning speed (m / min) Fracture strength (cN / dtex) Elongation at break (%) Application Example 1 93.1 4500 8.1 43 Application Example 2 92.6 4300 7.92 39.2 Application Example 3 94.2 4500 7.84 39.2 Application Example 4 93.8 4300 7.2 37.8 Application Example 5 94.5 4500 7.93 41.7 Application Example 6 89.3 3900 7.11 34.2 Application Example 7 81.1 3400 5.93 22.7 Application Example 8 86.3 3600 6.61 28.4 Application Example 9 79.6 2900 5.1 23.2 Application Example 10 82.3 3600 6.1 32.1 Application Example 11 89.3 3800 5.7 30.1 Application Example 12 91.3 4300 6.7 36.8 Application Example 13 85.1 3900 6.3 35.2 Comparative Application Example 1 79.5 3300 5.25 21.2 Comparative Application Example 2 92.1 4400 7.3 46.3 Comparative Application Example 3 89 3700 6.3 39.1 Comparative Application Example 4 85 2600 6.4 37 Comparative Application Example 5 93.1 4400 6.5 45.2

[0180] Based on the data in Tables 1 and 2, it can be seen that:

[0181] (1) The antistatic flame-retardant polyamide 66 resins provided in Examples 1 to 13 have excellent mechanical properties, flame retardant properties and spinnability. In particular, the antistatic flame-retardant polyamide 66 resins provided in Examples 1 to 5 have achieved the best mechanical properties, flame retardant properties and spinnability.

[0182] Specifically, the notched impact strength of the statically resistive flame-retardant polyamide 66 resin provided in Examples 1-5 is 6.2-7.2 kJ / m. 2 The tensile strength is 75–82.6 MPa, the elongation at break is 250–265%, the char formation rate is fast and the char layer is very dense. The vertical burning rating can reach V-0 level, and the limiting oxygen index reaches 32–34%. Furthermore, the antistatic flame-retardant polyamide 66 fiber filaments provided in Application Examples 1–5 have a full roll rate of 93.1–94.5%, a maximum spinning speed of 4300–4500 m / min, a breaking strength of 7.2–8.1 cN / dtex, and an elongation at break of 37.8–43%.

[0183] (2) Compared with Example 3, the polyamide 66 resin provided in Comparative Example 1 is a mixed flame retardant of organic reactive flame retardant and inorganic flame retardant, which is made by simple physical mixing. As a result, its notched impact strength, tensile strength and elongation at break are all low, and its mechanical properties are poor. At the same time, the antistatic flame retardant polyamide 66 fiber filaments further produced have a low full roll rate, a slow maximum spinning speed, and low breaking strength and elongation at break, indicating poor spinnability.

[0184] (3) Compared with Example 3, Comparative Example 2 did not add inorganic flame retardant zinc borate, resulting in a slow char formation rate and poor flame retardancy of the obtained polyamide 66 resin.

[0185] (4) Compared with Example 3, Comparative Examples 3 and 4 did not add heat stabilizer and antistatic agent during the salt formation stage, resulting in a decrease in the mechanical properties of the obtained polyamide 66 resin.

[0186] (5) Compared with Example 3, the amount of composite additive added in Comparative Example 5 was lower, which also resulted in a slow charring rate and poor flame retardancy of the obtained polyamide 66 resin.

[0187] The applicant declares that this invention illustrates an antistatic and flame-retardant polyamide 66 resin, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. An antistatic flame-retardant polyamide 66 resin, characterized in that, The raw materials for preparing the antistatic flame-retardant polyamide 66 resin include the following components in parts by weight: 90-120 parts by weight of polyamide 66 salt; 1-14 parts by weight of compound additive; Catalyst: 0.1 to 1 part by weight; The composite additive includes an organic reactive flame retardant and an inorganic flame retardant, and is obtained by ball milling the organic reactive flame retardant and the inorganic flame retardant together.

2. The antistatic flame-retardant polyamide 66 resin according to claim 1, characterized in that, The mass ratio of the organic reactive flame retardant to the inorganic flame retardant is (1-5):1; Furthermore, in the composite additive, the content of the organic reactive flame retardant is 0.5 to 7 parts by weight, and the content of the inorganic flame retardant is 0.5 to 2 parts by weight; Preferably, the average particle size of the composite additive is 0.1–3 μm, more preferably 0.5–1 μm; Preferably, the organic reactive flame retardant includes any one or a combination of at least two of bis-(p-benzoic acid)-phenyl-phosphoramide, bis-(p-benzoic acid)-phenyl-phosphoramide-hexanediamine pre-flame retardant, or bis-N-phenyl-3-amino-melamine-phenylphosphoramide-adipic acid pre-flame retardant; Preferably, the inorganic flame retardant includes any one or a combination of at least two of zinc borate, calcium oxide, zinc oxide, or aluminum oxide, and more preferably zinc borate.

3. The antistatic flame-retardant polyamide 66 resin according to claim 1 or 2, characterized in that, The raw materials for preparing the antistatic and flame-retardant polyamide 66 resin also include 0.1 to 5 parts by weight of antistatic agent; Alternatively, the composite additive may further include 0.1 to 5 parts by weight of an antistatic agent, and the composite additive is obtained by ball milling the organic reactive flame retardant, the inorganic flame retardant, and the antistatic agent together; Preferably, the antistatic agent comprises an amphoteric antistatic agent; Preferably, the amphoteric antistatic agent comprises any one or a combination of at least two of dodecyl dimethyl quaternary acetate, dodecyl dicarboxymethyl ammonium acetate, or alkyl dicarboxymethyl ammonium acetate; Preferably, the rotational speed of the ball mill is 200–500 rpm; Preferably, the ball milling time is 15–120 min; Preferably, the ball milling includes wet ball milling or dry ball milling, and more preferably wet ball milling.

4. The antistatic flame-retardant polyamide 66 resin according to any one of claims 1 to 3, characterized in that, The raw materials for preparing the antistatic and flame-retardant polyamide 66 resin also include 0.1 to 1 part by weight of heat stabilizer; Preferably, the heat stabilizer includes any one or a combination of at least two of the following: phosphite stabilizers, hindered amine stabilizers, or triazine stabilizers.

5. A method for preparing the antistatic flame-retardant polyamide 66 resin according to any one of claims 1 to 4, characterized in that, The preparation method is as follows: The first method involves a composite additive that does not contain an antistatic agent, comprising: mixing a polyamide 66 salt solution, a composite additive, a catalyst, an optional geothermal stabilizer, and an optional antistatic agent; the resulting mixture is then concentrated and polymerized to obtain the antistatic and flame-retardant polyamide 66 resin. Alternatively, the second method involves a composite additive containing an antistatic agent, comprising: mixing a polyamide 66 salt solution, a composite additive, a catalyst, and an optional geothermal stabilizer, and then concentrating and polymerizing the resulting mixture to obtain the antistatic and flame-retardant polyamide 66 resin.

6. The preparation method according to claim 5, characterized in that, The polyamide 66 salt solution contains 50-60% polyamide 66 salt by mass. Preferably, the concentration temperature is 150–160°C; Preferably, the concentrated salt solution obtained after concentration contains 70-80% polyamide 66 salt by mass. Preferably, the polymerization reaction specifically includes: 1) feeding the concentrated salt solution obtained after concentration into the polymerization reactor as the reactant, reacting at a pressure of 1-2 MPa for 0.5-1.5 h, and the temperature of the resulting reactant is 220-260 °C; 2) after unloading to atmospheric pressure, raising the temperature of the reactant to 270-280 °C; 3) evacuating to 0-0.1 MPa and reacting for 5-10 min; 4) pressurizing to 0.2-0.4 MPa, cooling and pelletizing to obtain the antistatic flame-retardant polyamide 66 resin.

7. A type of antistatic flame-retardant polyamide 66 fiber, characterized in that, The material of the antistatic flame-retardant polyamide 66 fiber includes the antistatic flame-retardant polyamide 66 resin as described in any one of claims 1 to 4.

8. A method for preparing antistatic flame-retardant polyamide 66 fiber filament as described in claim 7, characterized in that, The preparation method is as follows: melt spinning antistatic and flame-retardant polyamide 66 resin to obtain the antistatic and flame-retardant polyamide 66 fiber filament.

9. The preparation method according to claim 8, characterized in that, The melt spinning temperature is 275–285°C.

10. The application of the antistatic flame-retardant polyamide 66 fiber as described in claim 7 in the manufacture of automobiles or electronic appliances.

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